OPTICAL-PROPERTIES OF QUASI-PERIODIC AND APERIODIC PBS-CDS SUPERLATTICES

The transmission spectra of quasiperiodic Fibonacci superlattices and aperiodic Thue-Morse superlattices of the system PbS-CdS at room tempe rature and at 77 K are investigated. The superlattices are fabricated by pulsed laser-beam evaporation. The spectrum of optical transitions of the aperiodic superlattice is much richer than implied by a calcula tion of the spectrum of periodic superlattices. This is a consequence of the fractal structure of the energy spectrum of the aperiodic super lattices. Self-similarity is observed in the energy spectra of Thue-Mo rse lattices. (C) 1997 American Institute of Physics.